Answer: -3x
Step-by-step explanation: If you separate out each term on its own, 9 and x², and do the square root of each one, you are left with 3x. This is also coincidentally what the right side of this graph looks graphically. However, the line of 3x does continue past x=0, so the other side of this graph, -3x, fits this better.
Thats my best guess, either way, hope it helps!
